Heretofore, there are already known an electric automobile that drives the vehicle with driving force from a dynamo-electric machine such as a motor, a so-called hybrid automobile including the dynamo-electric machine combined with an engine that is an internal combustion engine, and the like. These electric vehicles are generally mounted with an electric power conversion device including a DC/DC converter device that receives direct current power from a high voltage battery as a direct current power supply and converts the received direct current power into direct current power having a different voltage value, and outputs the direct current power, and an inverter device that receives the direct current power from the DC/DC converter, converts the received direct current power into alternating power, and drives a motor.
In the electric power conversion device including the DC/DC converter and the inverter, more specifically, it is possible to aim to downsize the overall electric power conversion device by accommodating the DC/DC converter and the inverter in a shared casing to form a module. For example, in Patent Literature 1 below, a structure to realize the downsizing of a device is proposed in which a smoothing capacitor for a DC/DC converter provided on the input side of the DC/DC converter and a smoothing capacitor for an inverter provided on the input side of the inverter are accommodated in a shared capacitor package.